PB1827: ACUTE PROMYELOCYTIC LEUKEMIA IN THE ELDERLY
Authors: I. Marques, C. Sol, A. L. Pinto, E. Aguiar, M. L. Amorim, M. J. Soares, R. Bergantim, P. Gomes, F. Trigo
Journal: HemaSphere (2022)

Background: Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia characterized by the fusion of the PML-RARA. Its incidence in the population aged ≥60 years is lower than that observed in other AML, leading to little knowledge about this pathology in this type of population with specific characteristics Aims: Descriptive analysis of elderly patients with APL Methods: Retrospective review of APL patients, aged ≥60 years followed up in a tertiary hospital (2005-2021). Data analysis was performed using the program IBM SPSS Statistics 26® Results: It was included 47 patients [42,6% male (n=20), 57,4% female (n=27)], median age at diagnosis of 70 years (61-81), median Eastern Cooperative Oncology Group performance status (ECOG PS) 1 (0-2) and median Charlson Comorbidity Index (CCI) 6 (2-9). Considering the Sanz risk score, 29,8% patients (n=14) had low risk, 38,3% patients (n=18) had intermediate risk and 31,9% patients (n=15) had high risk. There was expression of aberrant markers in 36,2% of patients (n=17), namely CD56 (63,8%, n=30), CD34 (63,8%, n=30) and CD2 (4,3%, n=2). Additional karyotype alterations were observed in 14,9% patients (n=7) [addition of chromosome 8 (n=3), complex karyotype (n=2), t(1;5) (n=1) and t(1;3) (n=1)]. PML-RARA breakpoint was type BCR1/2 in 23 patients (48,9%) and type BCR3 in 21 patients (44,7%). Treatment was selected according protocols used in the service [AIDA/GIMENA (n=35, 74,5%), PETHEMA-LPA (n=10, 21,2%), or no treatment (n=2, 4,3%)]. During induction treatment, 14 patients (29,8%) died in a median of 11 days (1-53), due to cerebral hemorrhage/ischemia (n=8), sepsis/infection (n=3), cardiogenic shock (n=2) and ATRA differentiation syndrome (n=1). Considering the patients who died from a cerebral hemorrhage/ischemia event, in only 1 patient the event occurred during induction and in the remaining patients it was already present at the time of disease presentation. 33 patients achieved a complete response to induction treatment. Disease relapse was seen in 7 patients. To determine factors with impact on overall survival and response to therapy, a univariate logistic regression analysis was performed, and no association was found with age at diagnosis, ECOG PS, ICC, hemoglobin, leukocytes, platelets, fibrinogen, D-dimers, DHL, creatinine, albumin, additional karyotype changes, PML-RARA breakpoint type and aberrant marker expression. The OS was not reached and PFS was 13 months [median follow-up time 22 months (0-157)] and this results was similar in the patient aged <70 and ≥70 years (OS not reached in both groups, PFS was 12 and 13 months in patient aged <70 years and ≥70 years, respectively) Summary/Conclusion: Real-life studies evaluating elderly population of APL patients are scarce, however the characteristics of the population studied in this study do not differ from previously published series. Death of the patients studied during induction treatment occurred in a significant proportion of patients mainly due to cerebral hemorrhage/ischemia event, in which in almost all cases it was already present at the time of diagnosis. Although no correlation has been identified between the characteristics of patients, analytical parameters and molecular, cytogenetic and immunophenotypic features and the response to treatment and OS, early death may be due to clinical and biological aspects of the elderly patient not included in this assessment. Future studies in this population should include a detailed characterization of comorbidities and additional analytical parameters of these patients and not just the use of comorbidity assessment scales